DR Congo

Why it sticks

1. 1

   Africa's second-largest country; Kinshasa is the largest French-speaking city in the world.

2. 2

   The Congo River is the deepest river on Earth (over 220 m) and crosses the equator twice.

3. 3

   It was King Leopold II's private 'Congo Free State', then Belgian Congo, and was called Zaire from 1971 to 1997.

4. 4

   It produces about 70% of the world's cobalt, a key metal in phone and car batteries.

• Signs in French; Lingala and Swahili are widely spoken.
• Flag: sky blue with a red diagonal stripe edged in yellow and a yellow star in the top corner.
• Dense rainforest, red dirt roads and the very wide Congo River.